A wide range of adhesive articles are used in medical applications. These adhesive articles include gels used to attach electrodes and other sensing devices to the skin of a patient, a wide range of tapes to attach medical devices to a patient, and adhesive dressings used to cover and protect wounds.
Many of the adhesive articles use pressure sensitive adhesives. Pressure sensitive adhesives are well known to one of ordinary skill in the art to possess certain properties at room temperature including the following: (1) aggressive and permanent tack, (2) adherence with no more than finger pressure, (3) sufficient ability to hold onto an adherend, and (4) sufficient cohesive strength to be removed cleanly from the adherend. Materials that have been found to function well as pressure sensitive adhesives are polymers designed and formulated to exhibit the requisite viscoelastic properties resulting in a desired balance of tack, peel adhesion, and shear strength. The most commonly used polymers for preparation of pressure sensitive adhesives are natural rubber, synthetic rubbers (e.g., styrene/butadiene copolymers (SBR) and styrene/isoprene/styrene (SIS) block copolymers), various (meth)acrylate (e.g., acrylate and methacrylate) copolymers, and silicones.
One problem with using adhesive articles for medical applications is that the removal of adhesive article can cause trauma to the skin. This is particularly troublesome in patients with sensitive skin, such as infants and the elderly, and can become severe with chronic patients where adhesive articles are repeatedly attached and removed over a long term period.
Various attempts have been made to mitigate this problem with adhesive articles. In particular, health care professionals utilized removal techniques to mitigate skin trauma. One way to mitigate trauma to the skin is to remove the adhesive article using a slow peel at a high angle to avoid stretching the skin. Another way to mitigate trauma, when the adhesive article is stretchable, is to pull straight out (as close to a 0° angle as possible) to induce stretch releasing of the adhesive layer from the skin. Also, manufactures of adhesive articles have developed articles that mitigate skin trauma. So called “gentle-to-skin adhesives” have been developed that provide sufficient adhesion to skin to adhere the adhesive article to the skin, but do not strip of skin cells significantly when removed.
A variety of gentle-to-skin adhesives and dressings that use gentle-to-skin adhesives have been described. A gentle-to-skin adhesive is described in US Patent Publication No. 2011/0212325 (Determan et al.) which describes an electron beam and gamma radiation crosslinked silicone gel adhesive that may use either nonfunctional or functional poly diorganosiloxanes. In the European Patent No. EP 2,001,424 (Cotton) adhesive laminate dressings are described that include a hydrophobic gel adhesive useful as the skin contact layer, and also containing a structural layer having the gel adhesive on one side and a pressure sensitive adhesive on the other side. Also, U.S. Pat. No. 5,891,076 (Fabo) describes a hypertrophic scar dressing that includes silicone-gel on that side of the dressing which lies against the user's skin and a flexible carrier sheet embodied within the silicone-gel such tht the gel forms continuous layers on both sides of the carrier, and US Patent Publication No. 2010/0331785 (Fabo et al.) describes a dressing that includes a liquid impermeable film layer coated with a skin friendly adhesive on the side intended to adhere to the skin.
A variety of silicone pressure sensitive adhesives and blends of silicone pressure sensitive adhesives have been described. In U.S. Pat. No. 4,831,070 (McInally et al.) a composition suitable for use as a medical adhesive is described with contains a curable mixture of (A) a copolymer containing triorganosiloxy units and (B) a polydiorganosiloxane fluid containing hydroxyl groups, an organosilicon compound with more than two silicon-bonded alkoxy groups per molecule, and a condensation catalyst. In the Canadian Patent Publication No. 711,756 (Pail), a pressure sensitive adhesive is prepared by heating a mixture at a temperature above 100° C. of (1) 45-75 weight % of a resin copolymer with SiO2 and R3SiO1/2 units; (2) 25-55 weight % of a hydroxyl endblocked polydiorganosiloxane fluid, and (3) 0.001-5 weight % of an aliphatic organic amine compound. In US Patent Publication No. 2012/0095109 (Garaud et al.) adhesive films include (a) a polyoransiloxane resin composed of M and Q units, (d) a hydrosilation catalyst and at least one of (b) a polyorganosiloxane compound having at least 2 Si—H groups, or (c) a telechelic polyorganosiloxane compound having terminal Si—H groups. In US Patent Publication No. 2011/0028647 (Sixt et al.) room temperature crosslinkable materials are described that are based on organosilicon compounds and a catalyst containing a metal of the main or subgroup I or II in conjunction with an inorganic acid. US Patent Publication 2007/0202245 (Gantner et al.) describes a method for adhering a medical substrate to a human or animal using a silicone gel containing a hydroxyl substituted siloxane resin. US Patent Publication 2005/0282977 (Stempel et al.) describes a pressure sensitive adhesive composition comprising a blend of (1) a gel comprising a copolymer of an organosiloxane and siloxane having a plurality of reactive functionalities and a crosslinking agent, and (2) a pressure sensitive adhesive that is non-reactive with the gel. In U.S. Pat. No. 6,881,807 (Terada et al.) a curable silicone gel comprising (A) a polyorganosiloxane, (C) an addition-reaction platinum catalyst, (D) an organosilicon compound, and (E) an organic titanium compound.
Medical articles are described in US Patent Publication No. 2012/0029455 (Perez-Foullerat et al.), which describes wound dressings with gel adhesives, and US Patent Publication No. 2012/0135225 (Colas et al.) which describes a multi-layer transdermal patch comprising a non-curing pressure sensitive adhesive that has a therapeutic agent blended with it. Medical sealants are described in PCT Publication No. 2012/069794 (Phillips et al.) which describes a two part tissue sealant with part A comprising alkenyl-group containing prepolymers, and part B comprising prepolymers containing Si—H groups, and a catalyst.